1. Field of the Invention
The present invention relates to a connecting structure for opening and closing the connecting portions of sheets by slide fasteners. More particularly, the invention relates to a sheet-connecting structure for sheets to be opened or closed by slide fasteners, which can be applied for example to an opening and closing portion of a hood for a truck bed or a tent used for camping or mountain-climbing or to a connecting portion of a sheet for forming an agricultural tunnel or a portion for connecting sheets to each other at a building site or the like.
2. Brief Description of the Prior Art
A slide fastener is disposed on both sides of an opening of a sheet or the like to open or close the opening of the sheet or the like.
When this slide fastener is used in a place where any substantial tensile force acting in the lateral direction is not imposed, opening or closing of the fastener can be performed very smoothly, but when a strong tensile force acts in the lateral direction, the sliding movement of the fastener becomes subject to a great resistance, which causes the slide fastener to be very hard to open or close.
For example, in the case where a slide fastener is attached to an opening and closing portion of a hood of a truck, if the hood is pulled up on the stretched state, it becomes difficult to open or close the fastener. On the other hand, if the hood is pulled up in a relaxed state, though opening and closing of the fastener becomes easy, the hood sheet is not tightly set and is therefore readily flapped by wind during driving, and it is likely that the slide fastener is subjected to an excessive force application to lose its function in a short period of time.
Thus, in spite of the fact that the opening or closing operation with use of a slide fastener itself does not involve a particular problem, there has been a difficulty involved in the application of a slide fastener to sheets which must always be kept tightly stretched.